A tumor with a functional nerve growth factor receptor may be dependent on the neurotrophin nerve growth factor for survival and may regress in its absence, allowing a new approach to the treatment of certain patients with neuroblastoma.
We have used the human neuroblastoma cell line SH-SY5Y as a model system to investigate the expression and regulation of the receptors for brain-derived neurotrophic factor (BDNF), a member of the nerve growth factor (NGF) family of neurotrophins.
Here we demonstrate that NGF-but not neurotrophin-3 (NT-3) or brain-derived neurotrophic factor (BDNF)-induced apoptosis in p75NTR-expressing human neuroblastoma SK-N-MC cells.BDNF prevented NGF-induced apoptosis.
Extracellular-regulated kinases and phosphatidylinositol 3-kinase are involved in brain-derived neurotrophic factor-mediated survival and neuritogenesis of the neuroblastoma cell line SH-SY5Y.
We tested whether brain derived neurotrophic factor (BDNF) protects neuroblastoma (NB) cells from cytotoxic agents using a model NB cell line, NB 1643, which expresses functional tropomyosin related kinase B (TRKB) following treatment with all-trans-retinoic acid.TRKB is the receptor for BDNF.
SK-N-BE neuroblastoma cell clones transfected with p75(NTR) and lacking Trk neurotrophin receptors, previously reported to undergo extensive spontaneous apoptosis and to be protected by nerve growth factor (NGF) (Bunone, G., Mariotti, A., Compagni, A., Morandi, E., and Della Valle, G. (1997) Oncogene 14, 1463-1470), are shown to exhibit (i) increased levels of the pro-apoptotic lipid metabolite ceramide and (ii) high activity of caspases, the proteases of the cell death cascade.
We transfected the neuroblastoma line SH-SY5Y, which has endogenous expression of BDNF, with a full-length TrkB expression vector, and obtained clones with moderate or high levels of expression.
By using neuroblastoma cell clones lacking the expression of all neurotrophin receptors or engineered to express full-length or various truncated forms of p75(NTR), we could show that p75(NTR) is involved in the direct signaling of cell death by Abeta via the function of its death domain.
This shows that MYCN overexpression per se is not sufficient to induce trkB expression. trkB expression and BDNF responsiveness in neuroblastoma cells can be induced by all-trans-retinoic acid (RA).
We analysed neurotrophin receptor (NTR) expression of neuroblastoma cells by surface biotinylation assays and applied recombinant nerve growth factor (NGF), brain-derived neurotrophic factor, neurotrophin-3 and neurotrophin-4/5 to these cell lines assessing their survival and proliferation in long-term assays lasting 6 days.
However, the spontaneous regression of neuroblastoma mimics the programmed cell death normally occurring in developing sympathetic cells expressing both TrkA tyrosine kinase A and p75NTR neurotrophin receptor.
In the present study, we examined the regulation of FOXO3a by brain-derived neurotrophic factor (BDNF) in retinoic acid (RA)-differentiated human SH-SY5Y neuroblastoma cells.
By using a neuroblastoma cell line devoid of neurotrophin receptors and engineered to express either a full-length or a death domain (DD)-truncated form of p75NTR, we demonstrated that Abeta peptide activates the mitogen-activated protein kinases (MAPKs) p38 and c-Jun N-terminal kinase (JNK).
These results indicate that Akt is a key signaling component by which BDNF activation of the TrkB signal transduction pathway protects neuroblastoma cells from chemotherapy-induced cell death.
Expression of neurotrophin receptors of the tyrosine kinase receptor (Trk) family is an important prognostic factor in solid tumors including neuroblastoma.